Flow sensor devices and systems

ABSTRACT

A flow rate assembly can include a housing having a measurement channel extending along the housing axis and through a portion of the housing between the first and second ends of the housing, an outer cup portion positioned at least partly within the housing, and a transducer positioned within the outer cup portion and sealed from fluid flow past the outer cup portion, the transducer having a width perpendicular to the housing axis and greater than the width of the measurement channel, the transducer configured to generate an ultrasonic signal and to direct the ultrasonic signal through the measurement channel.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/713,440, filed Sep. 22, 2017, titled FLOW SENSOR DEVICES AND SYSTEMS,which claims the benefit under 35 U.S.C. 119(e) to U.S. Provisional App.No. 62/399,216, filed Sep. 23, 2016, titled FLOW SENSOR DEVICES ANDSYSTEMS. The entire contents of the above-identified patent applicationsare incorporated by reference herein and made a part of thisspecification. Any and all applications for which a foreign or domesticpriority claim is identified in the Application Data Sheet as filed witheh present application are hereby incorporated by reference under 37 CFR1.57.

TECHNICAL FIELD

Certain embodiments discussed herein relate to devices and systems formeasuring flow rate of fluid through pipes.

DISCUSSION OF THE RELATED ART

Many varieties of ultrasonic transducer assemblies exist, employing avariety of techniques and mechanisms for installing the transducerassemblies on a fluid conduit. However, such devices and certaincomponents thereof have various limitations and disadvantages.

SUMMARY OF THE INVENTIONS

Traditionally, clamp-on transducers have been favored by ultrasonic flowmeter manufacturers due to their one-size-fits-all transducer designthat simplifies manufacturing and minimizes inventory. Clamp-ontransducer type flow meters may be preferred because they have no movingparts, no wetted materials, and do not require a system shut-down forinstallation.

However, traditional clamp-on transducers require multiple installationdetails in order to operate correctly, such as: pipe material, pipe wallthickness, pipe inside diameter, pipe liner (if any), and fluid type.Furthermore, additional installation details are often difficult toobtain and detect, such as: the smoothness of the outer pipe wall, thesmoothness of the inner pipe wall (defects in surface), and theeccentricity of the pipe (which may not be zero). The inner wallsmoothness and eccentricity of the pipe are difficult to determine inthe field and can drastically affect the accuracy of clamp-on ultrasonicflow meters.

Clamp-on transducers require a silicon grease (or similar substance)between the outer pipe wall and the bottom of the transducer to fill andeliminate any air gaps. This grease needs to be replaced periodically,especially in outdoor or dry locations, leading to increased maintenancerequirements.

Due to the number of installation details needed for a successfulinstallation of clamp-on ultrasonic transducers, successful installationmay not occur in every situation. Additionally, clamp-on transducers aresusceptible to being unintentionally moved by external forces, such as apassers-by knocking or hitting transducers by mistake. Any shift in theclamp-on transducer can jeopardize the flow measurement accuracy.

Installing clamp-on transducers can often frustrate an installer that isnew to this type of technology. Even for those familiar with theprocess, properly addressing the plumbing details required forinstallation can be difficult, resulting in prolonged installation timeperiods.

While in-line transducers have also been developed, they suffer fromperformance challenges.

According to some variants, a flow rate assembly includes a housinghaving a housing axis, a first end having an inlet positioned along thehousing axis, a second end having an outlet positioned along the housingaxis, and/or a measurement channel extending along the housing axis andthrough a portion of the housing between the first and second ends ofthe housing, the measurement channel having a width perpendicular to thehousing axis. In some embodiments, the assembly includes an outer cupportion positioned at least partly within the housing. The outer cupportion can include a head portion connected to a wall of the housing,an elongate portion connected to the head portion, the elongate portionhaving a first face facing the measurement channel, and/or at least oneflow channel through the head portion configured to permit fluid to flowpast the outer cup portion through the at least one flow channel. Theassembly can include a transducer positioned within the elongate portionand sealed from fluid flow past the outer cup portion, the transducerhaving a width perpendicular to the housing axis and greater than thewidth of the measurement channel, the transducer configured to generatean ultrasonic signal and to direct the ultrasonic signal through themeasurement channel. In some embodiments, a ratio of a distance betweenthe first face of the elongate portion and the measurement channel, asmeasured parallel to the housing axis, to the width of the transducer isless than 4:5. In some embodiments, the first and second ends of thehousing are configured to mate with open pipe end in an in-line manner.

In some embodiments, the assembly includes a second outer cup portionpositioned at least partially within the housing. The second outer cupportion can include an outer head portion connected to a wall of thehousing, an elongate portion connected to the head portion, and/or atleast one flow channel through the head portion configured to permitfluid to flow past the outer cup portion through the at least one flowchannel. In some embodiments, the assembly includes a second transducerpositioned within the elongate portion of the second outer cup portionand sealed from fluid flow past the second outer cup portion, the secondtransducer having a width perpendicular to the housing axis and greaterthan the width of the measurement channel. In some embodiments, thesecond transducer is configured generate an ultrasonic signal and todirect the ultrasonic signal through the measurement channel toward thefirst transducer.

In some embodiments, the outer cup portion comprises at least oneboundary wall extending between the head portion and the elongateportion and forming a boundary of the at least one flow channel, whereinthe at least one boundary wall is configured to straighten flow throughthe at least one flow channel.

In some embodiments, the outer cup portion includes an outlet channelextending between an interior of the elongate portion and an exterior ofthe elongate portion.

In some embodiments, the outlet channel extends through the at least oneboundary wall.

In some embodiments, the housing comprises a first housing portion, asecond housing portion, and third housing portion positioned between thefirst and second housing portions, wherein the measurement channelextends through the third housing portion.

In some embodiments, one or more electrical components are positionedwithin a space between the third housing portion and the first housingportion.

According to some variants, a flow rate assembly can include a housinghaving a housing axis, a first end having an inlet positioned along thehousing axis, a second end having an outlet positioned along the housingaxis, a measurement channel extending along the housing axis and througha portion of the housing between the first and second ends of thehousing, the measurement channel having a width perpendicular to thehousing axis, and/or a first housing chamber between the measurementchannel and the inlet, as measured along the housing axis, the firsthousing chamber having a tapered inner wall. The assembly can include anouter cup portion positioned at least partly within the first housingchamber. The outer cup portion can include a head portion connected to awall of the housing, an elongate portion connected to the head portion,the elongate portion having a tapered portion between the first face andthe inlet and the measurement channel, and/or at least one flow channelthrough the head portion configured to permit fluid to flow past theouter cup portion through the at least one flow channel. The assemblycan include a transducer positioned within the elongate portion andsealed from fluid flow past the outer cup portion, the transducer havinga width perpendicular to the housing axis and greater than the width ofthe measurement channel, the transducer configured to generate anultrasonic signal and to direct the ultrasonic signal through themeasurement channel. In some embodiments, the tapered inner wall of thefirst housing chamber is substantially the same shape as the taperedportion of the elongate portion of the outer cup portion.

In some embodiments, the outer cup portion is spin welded to thehousing.

In some embodiments, the assembly includes a cap positioned at the firstend of the housing and forming the inlet, wherein the cap is configuredto engage with an open fluid conduit.

In some embodiments, the cap is spin welded to the outer cup portion.

In some embodiments, the transducer is fluidly isolated from fluidflowing through the assembly.

In some embodiments, the assembly includes an inner cup portionpositioned at least partially within the elongate portion of the outercup portion, wherein the transducer is positioned within the inner cupportion and wherein a connection between the inner cup portion and theouter cup portion forms a seal to inhibit or prevent fluid ingress intothe elongate portion of the outer cup portion.

In some embodiments, the inner cup portion has a flat face facing themeasurement channel.

According to some variants, a flow rate assembly includes a housinghaving a housing axis, a first end having an inlet positioned along thehousing axis, a second end having an outlet positioned along the housingaxis, and/or a measurement channel extending along the housing axis andthrough a portion of the housing between the first and second ends ofthe housing, the measurement channel having a width perpendicular to thehousing axis. The assembly can include an outer cup portion positionedat least partly within the housing, the outer cup portion including ahead portion connected to a wall of the housing, an elongate portionconnected to the head portion, the elongate portion having a first facefacing the measurement channel, and at least one flow channel throughthe head portion configured to permit fluid to flow past the outer cupportion through the at least one flow channel. The assembly can includea transducer positioned within the elongate portion and sealed fromfluid flow past the outer cup portion, the transducer having a widthperpendicular to the housing axis and greater than the width of themeasurement channel, the transducer configured to generate an ultrasonicsignal and to direct the ultrasonic signal through the measurementchannel. In some embodiments, a ratio of a distance between the firstface of the elongate portion and the measurement channel, as measuredparallel to the housing axis, and the width of the measurement channelis less than 1:1.

In some embodiments, the housing comprises a first housing, a secondhousing, and a third housing positioned between the first and secondhousings, wherein the flow rate assembly includes at least one fastenerthat extends at least partially through each of the first, second, andthird housings to connect the first, second, and third housings to eachother.

In some embodiments, the flow rate assembly is configured to preciselyand accurately measure flow rates through the measurement channel as lowas 10 mL/min.

In some embodiments, the flow rate assembly is configured to preciselyand accurately measure flow rates through the measurement channel as lowas 5 mL/min.

In some embodiments, the width of the measurement channel isapproximately 0.25 inches.

BRIEF DESCRIPTION OF THE DRAWINGS

The present inventions are described with reference to the accompanyingdrawings, in which like reference characters reference like elements,and wherein:

FIG. 1 is a perspective view of a flow meter assembly.

FIG. 2 is a top elevational view of the flow meter assembly of FIG. 1.

FIG. 3 is a left side elevational view of the flow meter assembly ofFIG. 1.

FIG. 4 is a longitudinal cross-section view of the flow meter assemblyof FIG. 1, taken along the cut-plane 4-4 of FIG. 3.

FIG. 5 is a longitudinal cross-section view of the flow meter assemblyof FIG. 1, taken along the cut-plane 5-5 of FIG. 3.

FIG. 6 is an exploded perspective view of the flow meter assembly ofFIG. 1.

FIG. 7 is a perspective view of a sensor assembly of the flow meterassembly of FIG. 1.

FIG. 8 is a side elevational view of the sensor assembly of FIG. 7.

FIG. 9 is an exploded back side perspective view of the sensor assemblyof FIG. 7.

FIG. 10 is an exploded front side perspective view of the sensorassembly of FIG. 7.

FIG. 11 is a longitudinal cross-section view of the sensor assembly ofFIG. 7, taken along the cut-plane C-C of FIG. 8.

FIG. 12 is a longitudinal cross-section view of a meter housing of theflow meter assembly of FIG. 1, taken along the cut-plane 5-5 of FIG. 3.

FIG. 13 is a top plan view of another embodiment of a flow meterassembly.

FIG. 14 is a rear plan view of the flow meter assembly of FIG. 13.

FIG. 15 is a right-side plan view of the flow meter assembly of FIG. 13.

FIG. 16 is a perspective exploded view of the flow meter assembly ofFIG. 13.

FIG. 17 is a longitudinal cross-section view of the flow meter assemblyof FIG. 13, taken along the cut-plane 17-17 of FIG. 15.

FIG. 18 is a longitudinal cross-section view of the flow meter assemblyof FIG. 13, taken along the cut-plane 18-18 of FIG. 15.

FIG. 19 is a perspective view of an outer cup portion of the flow meterassembly of FIG. 13.

FIG. 20 is an end plan view of the outer cup portion of FIG. 19.

FIG. 21 is a cross-section view of the outer cup portion of FIG. 19,taken along the cut-plane 21-21 of FIG. 20.

DETAILED DESCRIPTION OF THE INVENTIONS

While the present description sets forth specific details of variousembodiments, it will be appreciated that the description is illustrativeonly and should not be construed in any way as limiting. Furthermore,various applications of such embodiments and modifications thereto,which may occur to those who are skilled in the art, are alsoencompassed by the general concepts described herein.

Ultrasonic transducer assemblies are used to measure flowcharacteristics of fluid flowing through pipes or other fluid lines. Thetransducer assemblies can include two or more transducers configured tosend and receive ultrasonic signals through the fluid line andcorresponding fluid. Transducer assemblies can indicate such parametersas the velocity of the fluid through the fluid line. Transducerassemblies can be used in conjunction with pumps and other devices tomonitor and/or control flow rates through fluid lines.

The transducers used in traditional transducer assemblies often must beprecisely aligned with the longitudinal axis of the fluid line on whichthey are installed. Misalignment of the transducers can increase thelikelihood that the ultrasonic signals sent from the first transducerwill not be received by the second transducer. Further, many transducerassemblies rely on reflection of the ultrasonic signals off of theinterior surface of the pipe. Thus, the assemblies must be carefullycalibrated to account for the pipe characteristics (e.g., size,material, etc.) as well as the fluid characteristics (e.g., composition,temperature, etc.).

Inline type ultrasonic flow meters can reduce installation time andimprove flow measurement accuracy since several difficult to determinevariables necessary for a successful installation may be removed. Inlineflow meters having axially-aligned transducers can reduce or eliminatethe need to reflect signals off of the interior walls of the pipe. Assuch, the transducers may not need to be realigned when used withdifferent fluid types.

Furthermore, some embodiments of an inline flow meter can reduceinventory holding cost. Since the annular diameter of the flow passageof the inline flow meter can be controlled at the time of manufacture,several models with varying annular diameters can be made. Externalpipes of varying diameters may be connected to each model of the inlineflow meter. Therefore, in some embodiments, an inline flow meter havinga given diameter may be used with a range of pipe diameters. Thisreduces the amount of inventory required while also improving themeasuring accuracy, due to the other variables, identified above, thatmay be controlled during manufacture of the flow meter.

An embodiment of a flow meter assembly 10 is illustrated in FIG. 1. Theflow meter assembly 10 has a first end 14 and a second end 18. The ends14, 18 of the sensor assembly 10 can be configured to connect in-linewith a pipe (not shown). In some embodiments, each of the first andsecond ends 14, 18 are similar or identical in structure.

The flow meter assembly 10 can include a central portion 20. The centralportion 20 can extend between the first and second ends 14, 18. In someembodiments, the first and second ends 14, 18 comprise respective caps22 a and 22 b. The central portion 20 can comprise a housing 26. Thehousing 26 can include a housing axis 27. The housing axis 27 can extendalong a length of the housing 26 and through the first and second ends14, 18 of the flow meter assembly 10. In some embodiments, the housingaxis 27 is parallel to the length of the housing 26. One or moresensors, transducer, and/or other components can be positioned withinthe housing 26 and/or within the caps 22 a, 22 b. The caps 22 a, 22 bcan be constructed separate from the housing 26 and can be connected toopposite ends of the housing 26 during assembly. In some embodiments,the caps 22 a, 22 b are removable from the housing 26 after assembly.

As illustrated in FIG. 2, each of the caps 22 a, 22 b can include firstmating portion 28 a, 28 b. The first mating portions 28 a, 28 b can beconfigured to couple with a pipe in an in-line manner. For example, thefirst mating portions 28 a, 28 b can each be configured to be insertedinto an end of a pipe. Fasteners, welding, adhesives, and/or otherconnection methods/structures can be used to connect the caps 22 a, 22 b(e.g., the first mating portions 28 a, 28 b) to the pipe ends. The caps22 a, 22 b can include apertures 32 a, 32 b (FIG. 4) configured tofacilitate fluid flow from the pipes through the housing 26.

As illustrated in FIGS. 2-3, the caps 22 a, 22 b can include secondportions 30 a, 30 b. The second portions 30 a, 30 b have a diameter D1greater than the diameter D2 of the first mating portions 28 a, 28 b.The second portions 30 a, 30 b can be configured to inhibit or preventover-insertion of the caps 22 a, 22 b into the pipes and/or into thehousing 26. For example, the second portions 30 a, 30 b can be sized toabut the ends of the pipes and the ends of the housing 26. The firstmating portions 28 a, 28 b can extend from the second portions 30 a, 30b.

Referring to FIG. 4, the caps 22 a, 22 b can include third portions 34a, 34 b. The third portions 34 a, 34 b can be connected to the secondportions 30 a, 30 b and extend in a direction opposite the first matingportions 28 a, 28 b. The third portions 34 a, 34 b can have outerdiameters that are sized to fit at least partially within the housing26. For example, the third portions 34 a, 34 b can be inserted into thehousing 26 when the caps 22 a, 22 b are mated with the housing 26. Theinner diameter D3 of the third portions 34 a, 34 b can greater than theinner diameter D4 of the apertures 32 a, 32 b. As illustrated, the innerdiameter D3 of the third portions 34 a, 34 b forms cap chambers 36 a, 36b. The cap chamber 36 a is in fluid communication with the aperture 32 ain the cap 22 a and the cap chamber 36 b is in fluid communication withthe aperture 32 b in the opposite cap 22 b.

The housing 26 can include one or more housing chambers 38 a, 38 b. Forexample, the inner diameter D5 of the housing 26 near the first andsecond ends 14, 18 of the assembly can define the housing chambers 38 a,38 b. The housing chambers 38 a, 38 b. The inner diameter D5 can begreater than the inner diameter D4 of the apertures 32 a, 32 b. In someembodiments, the inner diameter D5 defining the housing chambers 38 a,38 b can be within ±15%, within ±12%, within ±9%, and/or within ±5% ofthe inner diameter D3 of the third portions 34 a, 34 b of the caps 22 a,22 b.

The housing 26 can include a measurement channel 40. The measurementchannel 40 can extend along the housing axis 27 (FIG. 5). In someembodiments, the measurement channel 40 is straight and parallel to thehousing axis 27. The measurement channel 40 can have a diameter D6. Asillustrated, the measurement channel 40 can have a constant diameteralong its length. The diameter D6 of the measurement channel 40 can beless than one or both of the diameters D4, D5 of the cap chambers. Insome embodiments, the diameter D6 of the measurement channel 40 is lessthan ½, less than ⅓, less than ¼, and/or less than ⅕ of the diameter D5of the housing chambers 38 a, 38 b. In some applications, the diameterD6 of the measurement channel is less than or equal to 1 inch, less thanor equal to 0.75 inches, less than or equal to 0.5 inches, and/or lessthan or equal to 0.25 inches. For example, the diameter D6 of themeasurement channel 40 can be approximately 0.25 inches.

As illustrated in FIGS. 4-5, the flow meter assembly 10 can include oneor more sensor assemblies 44 a, 44 b. The sensor assemblies 44 a, 44 bcan be positioned within one or both of the cap chambers 36 a, 36 b andhousing chambers 38 a, 38 b. In some embodiments, the sensor assemblies44 a, 44 b are positioned outside of and on opposite sides of themeasurement channel 40.

The sensor assemblies 44 a, 44 b can each include an outer cup portion46 a, 46 b. The sensor assemblies 44 a, 44 b can each include atransducer assembly 54 a, 54 b. The transducer assembly 54 a, 54 b canbe positioned at least partially within the outer cup portion 46 a, 46b. The sensor assembly 44 a, 44 b can include a cap 56 a, 56 bconfigured to seal one side of the sensor assembly 44 a, 44 b andinhibit or prevent ingress of fluid into the sensor assemblies 44 a, 44b from the interior of the flow meter assembly 10. The flow meterassembly can include one or more seals 45 (e.g., O-rings) positionedbetween the sensor assemblies, 44 a, 44 b and the caps 22 a, 22 b,and/or housing 26.

In some embodiments, as discussed in more detail below, the sensorassemblies 44 a, 44 b include an outlet port 60 a, 60 b configured tofacilitate access of wires (not shown) or other components into thesensor assemblies 44 a, 44 b from outside of the flow meter assembly 10.As illustrated, the outlet ports 60 a, 60 b can be aligned with housingports 62 a, 62 b which extend through the walls of the housing 26. Wirespassed through the ports 60 a, 60 b, 62 a, 62 b can be connected tocontrollers, power sources, and/or other electrical components.Isolation of the wires from the fluid flowing through the meter assembly10 can allow for flow measurements without concern for corrosion of thewires or other components within the sensor assemblies 44 a, 44 b. Suchisolation can allow for flow rate measurement in corrosive chemicals andother fluids. One or more controllers (not shown) may be used to adjustcomponents within the flow meter 10 in response to changes in fluidtypes, temperatures, and other factors.

As illustrated in FIGS. 7-8, the outer cup portion 46 a, 46 b caninclude a head portion 48 a, 48 b. The outer cup portion 46 a, 46 b caninclude an elongate portion 52 a, 52 b. The elongate portion 52 a, 52 bcan be connected to the head portion 48 a, 48 b and extend therefrom ina direction parallel to the channel axis 27. One or more flow channels68 a, 68 b can be formed through the head portion 48 a, 48 b. The flowchannels 68 a, 68 b can facilitate fluid flow past the sensor assemblies44 a, 44 b through the flow meter assembly 10. The flow channels 68 a,68 b can be bounded by boundary walls 66 a, 66 b. The boundary walls 66a, 66 b can be curved form rounded ends to the flow channels 68 a, 68 b,as measured in a plane perpendicular to the channel axis.

The sensor assembly 44 a, 44 b can include a key feature 70 a, 70 b(e.g., a protrusion, indentation, or other keying feature). The keyfeature 70 a, 70 b can be configured to fit into or onto an alignmentfeature 72 a, 72 b (e.g., a protrusion, indentation, or other keyingfeature) of the housing 26. Interaction between the key feature 70 a, 70b and alignment feature 72 a, 72 b can help to ensure proper alignmentbetween the outlet ports 60 a, 60 b and the housing ports 62 a, 62 b.The head portion 48 a, 48 b can include one or more seal channels 77configured to receive and/or align the seal(s) 45.

Referring to FIGS. 9-10, the transducer assembly 54 a, 54 b can includean inner cup portion 76 a, 76 b. The inner cup portion 76 a, 76 b can beconfigured to house and/or receive a transducer 82 a, 82 b. In someembodiments, a transducer backing 83 a, 83 b can be positioned withinthe inner cup portion 76 a, 76 b behind the transducer 82 a, 82 b. Insome embodiments, the backing 83 a, 83 b is an elastomer, epoxy, orother material configured to inhibit transmission of ultrasonic signalsfrom the transducers 82 a, 82 b through the backing 83 a, 83 b.

As illustrated in FIG. 4, the transducer 82 a, 82 b can have a width ordiameter D7. The diameter D7 of the transducer can be greater than thediameter D6 of the measurement channel 40. For example, the diameter D6of the transducer 82 a, 82 b can be at least 5% greater, at least 8%greater, at least 12% greater, at least 25% greater, at least 35%greater, at least 50% greater, and/or at least 100% greater than thediameter D6 of the measurement channel 40. In some embodiments, thediameter D7 of the transducer 82 a, 82 b is at least 0.1 inches, atleast 0.2 inches, at least 0.25 inches, at least 0.3 inches, at least0.4 inches, at least 0.75 inches, and/or at least 1 inch. For example,the diameter D7 of the transducer 82 a, 82 b can be approximately 0.375inches.

Referring back to FIGS. 9-10, the inner cup portion 76 a, 76 b caninclude a head portion 78 a, 78 b. The inner cup portion 76 a, 76 b caninclude an elongate portion 80 a, 80 b connected to and extending fromthe head portion 78 a, 78 b. The transducer 82 a, 82 b can be positionedwithin the elongate portion 80 a, 80 b at or near the end of theelongate portion 80 a, 80 b opposite the head portion 78 a, 78 b.

The head portion 78 a, 78 b of the inner cup portion 76 a, 76 b can beconfigured to engage with a portion of the elongate portion 52 a, 52 b.In some embodiments, the head portion 78 a, 78 b of the inner cupportion 76 a, 76 b is welded, adhered, or otherwise connected to theelongate portion 52 a, 52 b or some other portion of the sensor assembly44 a, 44 b.

The elongate portion 52 a, 52 b can include a channel 84 a, 84 b. Thechannel 84 a, 84 b can extend through the entirety of the elongateportion 52 a, 52 b. In some embodiments, one end of the channel 84 a, 84b is closed (e.g., the end facing the opposite sensor assembly 44 a, 44b). The channel 84 a, 84 b can be sized and shaped to receive theelongate portion 80 a, 80 b of the inner cup portion 76 a, 76 b.

As illustrated in FIG. 11, the elongate portion 52 a, 52 b can have atapered end 86 a, 86 b (e.g., the end closest to the opposite sensorassembly 44 a, 44 b). In some embodiments, the elongate portion 52 a, 52b has an overall “bullet” shape. When assembled, the transducer 82 a, 82b can be positioned at or near the end of the elongate portion 52 a, 52b (e.g., the tapered end) opposite the head 48 a, 48 b. In someembodiments, this end of the elongate portion 52 a, 52 b has thesmallest diameter of any portion of the elongate portion 52 a, 52 b.

The transducer 82 a, 82 b can have an overall flat shape. For example,the transducer 82 a, 82 b can have a disc shape with a front side 88 a,88 b and a back side 90 a, 90 b. The front side 88 a, 88 b of thetransducer 82 a, 82 b can be the side facing the transducer 72 a, 72 bon the other end of the housing 26. The respective front sides 88 a, 88b can be parallel to each other and can be positioned along the housingaxis 27. Such alignment can facilitate successful transmission ofultrasonic signals between the two transducers 82 a, 82 b. In someembodiments, a wire conduit 92 a, 92 b is connected to the back side 90a, 90 b of the transducer 82 a, 82 b. The wire conduit 92 a, 92 b canhelp guide electrical wires away from the transducer 82 a, 82 b andtoward the outlet port 60 a, 60 b when the sensor assembly 44 a, 44 b isassembled.

The transducer 82 a, 872 b can be positioned along the housing axis 27.The width (e.g., diameter) of the transducer 82 a, 82 b can be greaterthan the diameter D6 of the measurement channel 40. The transducer 82 a,82 b can be positioned behind a portion of the inner cup portion 76 a,76 b through which the transducer 82 a, 82 b. For example, the inner cupportion 76 a, 76 b can include a wave guide portion 94 a, 94 b. The waveguide portion 94 a, 94 b can be on the end of the inner cup portion 76a, 76 b closest the measurement channel 40. The wave guide portion 94 a,94 b can have a wave guide face 96 a, 96 b facing toward the wave guideface 96 a, 96 b of the opposite sensor assembly 44 a, 44 b. The waveguide faces 96 a, 96 b can be flat and positioned along the housing axisto facilitate direction of the transducer signals parallel to thehousing axis 27. The wave guide faces 96 a, 96 b can be parallel to eachother. In some embodiments, the wave guide faces 96 a, 96 b have aconcave configuration to focus the transducer signals inward toward thehousing axis 27. In some embodiments, the wave guide 96 a, 96 b has aconvex shape to direct the ultrasonic waves outward toward the walls ofthe measurement channel 40.

As illustrated in FIG. 5, the wave guide faces 96 a, 96 b can bepositioned close to the ends of the measurement channel 40 as measuredparallel to the housing axis 27. In some embodiments, distance D8between the wave guide faces 96 a, 96 b and the ends of the measurementchannel 40 are less than 2 inches, less than 1.5 inches, less than 1inch, less than 0.75 inches, less than 0.55 inches, less than 0.3inches, and/or less than 0.1 inches, as measured parallel to the housingaxis 27. In some embodiments, the distance D8 between the wave guidefaces 96 a, 96 b and the measurement channel 40 is approximately 0.22inches, as measured parallel to the housing axis 27. Maintaining a closedistance between the wave guide faces 96 a, 96 b and the ends of themeasurement channel 40 can increase the quality of the measurementsobtainable by the transducers 82 a, 82 b. For example, maintaining aclose distance can reduce the turbulence in the flow by maintaining asmooth flow path between the flow channels 68 a, 68 b and themeasurement channel 40. This flow path can transition with relativelylittle or no diffusion from the flow channels 68 a, 68 b and themeasurement channel 40. Reducing turbulence in the flow between the waveguide faces 96 a, 96 b and the measurement channel 40 can reduce thenoise in the signal measured by the transducers 82 a, 82 b. In someembodiments, flow rates as low as 15 mL/min, as low as 10 mL/min, and/oras low as 5 mL/min can be measured.

The ratio between the distance D8 and the diameter D7 of the transducer82 a, 82 b can be less than 2:1, less than 3:2, less than 4:3, less than7:8, less than 3:4, less than 1:2, and/or less than 1:4. In someembodiments, the ratio between the distance D8 and the diameter D7 ofthe transducer 82 a, 82 b is approximately 3:5. The ratio between thedistance D8 and the diameter D6 of the measurement channel 40 can beless than 2:1, less than 5:4, less than 6:5, less than 8:9, less than1:2, less than 1:3, and/or less than 1:4. In some embodiments, the ratiobetween the distance D8 and the diameter D6 of the measurement channel40 is approximately 9:10. Maintaining close ratios between the distanceD8 and the diameters D6 and D7 can help to maintain a smooth flow at theentrance and exit of the measurement channel 40. Maintaining smooth flow(e.g., low turbulence) can reduce the noise in the signal measured bythe transducers 82 a, 82 b and can allow for measurement of small flowrates.

Referring to FIG. 12, the housing chamber 38 a, 38 b on either end ofthe housing 26 can have a tapered portion 98 a, 98 b. The taperedportion 98 a, 98 b can extend to the measurement channel 40.

Referring back to FIG. 5, the flow meter assembly 10 can be symmetricabout a plane (not shown) perpendicular to the housing axis 27 andpositioned halfway along the length of the housing 26. Each of the capapertures 32 a, 32 b, transducers 82 a, 82 b, and measurement channel 40can be positioned along the housing axis 27 to facilitate asubstantially straight fluid flow path through the flow meter assembly10.

Either of the cap apertures 32 a, 32 b can function as an inlet to theflow meter assembly 10, while the opposite cap aperture 32 a, 32 bserves as the outlet to the flow meter assembly 10. For the purposes ofdiscussion, the cap aperture 32 a on first end 14 will be referred to asthe inlet, while the cap aperture 32 b on the second end 18 will bereferred to as the outlet. Using inlets and outlets that are coaxial orotherwise aligned with the fluid flow path through the assembly 10 canreduce introduction of turbulence that would otherwise occur if lateralor oblique inlets/outlets were used.

Fluid (e.g., a liquid) that flows through the inlet 32 a passes into thecap chamber 36 a. The cap chamber 36 a can have filleted and/orchamfered internal surfaces to provide a smooth fluid flow surface.Providing a smooth flow surface can inhibit bubble generation within thefluid. The fluid in the cap chamber 36 a is directed through the flowchannels 68 a of the sensor assembly 44 a into the housing chamber 38 a.The boundary walls 66 a can reduce turbulence and/or straighten thefluid flow through the system. For example, the boundary walls 66 a caninhibit vertical fluid flow through the channels 68 a. The flowstabilization provided by the boundary walls 66 a, 66 b can permitpositioning of the flow meter assembly 10 closer to a bend in a pipingsystem than may have been possible without the boundary walls 66 a, 66b. The fluid then passes between the tapered end 86 a of the elongateportion 52 a and the tapered portion 98 a of the housing chamber 38 a.The fluid is accelerated into the measurement channel 40.

The flow rate of the fluid is measured by the transducers 82 a, 82 b asthe fluid flows through the measurement channel 40. Each of thetransducers 82 a, 82 b can send and receive ultrasonic signals whenmeasuring flow rate through the measurement channel 40. The fluid thenpasses between the tapered end 86 b of the elongate portion 52 b and thetapered portion 98 b of the housing chamber 38 b. After passing throughthe housing chamber 38 b, the fluid is directed through the channels 68b of the sensor assembly 44 b and into the cap chamber 36 b. The fluidthen passes out through the outlet 32 b and into the pipe with which thecap 22 b is mated.

Utilizing a narrow measurement channel 40 (e.g., a channel narrower thanthe transducers 82 a, 82 b) can facilitate accurate and reliablemeasurement of very low liquid flow rates. For example, a flow meterassembly 10 as described in the present disclosure can measure flowrates as low as 15 mL/min, as low as 10 mL/min, and/or as low as 5mL/min. Accurately measuring low flow rates such as those recited abovecan be especially beneficial in applications where chemicals or othercomponents need to be added to another fluid at a reliably low level(e.g., due to safety considerations). This is often needed in smallmunicipalities, individual homes, and other small scale water treatmentand/or water deliver environments.

Another advantage provided by the flow meter assembly 10 is the abilityto measure fluid velocity without needing to reflect ultrasonic signalsoff of the walls of the housing 26 or of any other component in thesystem. For example, flow meters which measure reflected signals mustprecisely align and position the transducers to ensure that the signalsfrom each transducer will be received by the other transducer. Suchalignment challenges in reflected-signal systems can be furtherexacerbated when the temperature and/or composition of the fluidchanges, as these changes can require repositioning/realignment of oneor both of the transducers. Further, imperfections, corrosion, sediment,and/or other abnormalities on the surface of the pipe walls canadversely affect the accuracy of reflected signals. Signal strength canalso suffer when the ultrasonic signals are reflected due to phenomenasuch as dispersion of the signal and absorption of a portion of thesignal by the reflecting surface. The above-recited challengesassociated with reflected-signal systems can be avoided by the flowmeter 10, as the ultrasonic signals generated by the transducers 82 a,82 b are sent directly to the opposite transducer without reflection.

In some embodiments, one or more of the components within the caps 22 a,22 b and/or housing 26 may be removed for cleaning, repair, or othermaintenance. For example, one of the caps 22 a, 22 b may be disconnectedfrom the housing 26, allowing a user access to the sensor assembly 44 a,44 b.

FIGS. 13-21 illustrate an embodiment of a flow meter assembly 110. Theflow meter assembly 110 includes some structures and functions that arethe same as or similar to the structures and functions described abovewith respect to the flow meter assembly 10. Components of the flow meter110 that are similar or the same in structure and/or function as thecomponents of the flow meter 10 are labeled with a like referencenumber, wherein a value of “100” is added. For example, the wave guidefaces 196 a, 196 b of the flow meter 110 are similar in structure andfunction as the wave guide faces 96 a, 96 b of the flow meter 10. Unlessotherwise noted below, the like components of the flow meter 110 are thesame as or similar in structure and/or function as the like elements ofthe flow meter 10.

As illustrated in FIGS. 13-15, the flow meter assembly 110 can include aplurality of housing components. For example, the flow meter assembly110 can include a first housing portion 126 a, and a second housingportion 126 b. The first and second housing portions 126 a, 126 b can besimilar in structure to each other and can be mirrored about thelongitudinal axis of the assembly 110. In some embodiments, one or bothof the first and second housing portions 126 a, 126 b can includeapertures 135 though which fasteners 131 or other components can beinserted. The fasteners 131 (FIG. 16) can be configured to hold thefirst and second housing portions 126 a, 126 b together when assembled.

The flow meter assembly 110 can include a third or inner housing portion126 c. The third housing portion 126 c can be positioned at leastpartially between the first and second housing portions 126 a, 126 b. Insome embodiments, a housing interior 123 (FIG. 17) is formed between thethird housing portion 126 c and the first and second housing portions126 a, 126 b. The fasteners 131 can be configured to pass through atleast a portion of the third housing 126 c to secure the third housing126 c to and/or between the

As illustrated in FIG. 16, the assembly 110 can include one or moreseals 127 a, 127 b. The seals 127 a, 127 b can be positioned between twoor more of the housing portions 126 a, 126 b, 126 c (collectively “126”)to seal the housing interior 123. In some embodiments, the seals 127 a,127 b are shaped and sized to match one or more surfaces of the housingportions 126. The seals 127 a, 127 b can be configured to seal theinterface between the third housing portion 126 c and the first housingportion 126 a, and the interface between the third housing portion 126 cand the second housing portion 126 b, respectively.

One or more electrical components (e.g., circuit boards, controllers,wireless or wired transmitters, batteries, sensors, memory units,processors, etc.) can be positioned at least partially within thehousing interior 123. As illustrated, electrical components 143, 145 canbe positioned on one or both sides of the third housing portions 126 c.Grommets 129 or other sealing structures can be used to facilitatepassage of wires and/or cables from an exterior of the housing portions126 to the housing interior 123. In some embodiments, the assembly 110is completely wireless and without holes or other access structures intothe housing interior 123 when the assembly 110 is assembled.

In some embodiments, two or more components of the assembly 110 areconnected to each other via spin welding. For example, the caps 122 a,122 b can be spin welded to the outer cup portions 146 a, 146 b of thesensor assemblies 144 a, 144 b. In some embodiments, the outer cupportions 146 a, 146 b are spin welded to the third housing 126 c. Spinwelding the components to each other can realize a number of benefits.For example, the spin welding process can create a chemical bond betweenthe welded components that can reduce or eliminate the need for usingseparate O-rings or other sealing structures. This can increase the lifeof the assembly 110 and reduce the need to replace the seals over time.In some configurations, as illustrated in FIG. 17, the voids 167 areformed in various portions of the assembly 110 to capture material(e.g., flakes, chips, or other material) generated during the spinwelding process.

Preferably, the various marked distances and diameters in FIG. 17 arethe same as or similar to the distances and diameters described abovewith respect to FIGS. 4 and 5. For example, widths/diameters D13, D14,D15, D16, and D17 can be the same as or similar to the widths/diametersD3, D4, D5, D6, and D7, respectively. The distance D18 can be the sameas or similar to the distance D8. As illustrated in FIG. 17, the waveguide faces 196 a, 196 b can extend beyond the inner cup portions 176 a,176, respectively, in a direction toward the measurement channel 40.This extension can create a step between the wave guide faces 196 a, 196b and the inner cup portions 176 a, 176 to inhibit or prevent formationof bubbles on wave guide faces 196 a, 196 b. The respective ratiosbetween the distances and widths/diameters in the assembly 110 can bethe same as or similar to those distances and widths/diameters describedabove with respect to assembly 10.

As illustrated in FIGS. 17 and 18, the inner walls of the housingchambers 138 a, 138 b can have the same or similar slopes/tapers as theelongate portions 152 a, 152 b of the outer cup portions 146 a, 146 b.Utilizing similar shapes, curves, and/or tapers between the inner wallsof the housing chambers and the outer walls of the elongate portions canreduce turbulence in the flow of fluid through the system, as instancesof nuzzling and diffusing can be reduced.

As illustrated in FIGS. 16-21, the outer cup portions 146 a, 146 b andthird housing 126 c can include one or more ports or channels throughwhich wires or cables can be inserted into an interior of the elongateportions 152 a, 152 b of the outer cup portions 146 a, 146 b. Asillustrated in FIG. 21, outlet channels 160 a, 160 b can extend throughthe boundary walls 166 a, 166 b of the outer cup portion 146 a, 146 b.The outlet channels 160 a, 160 b can have inner ports 163 a, 163 b andouter ports 165 a, 165 b. The outlet channels 160 a, 160 b can bealigned with housing ports 162 a, 162 b to facilitate passage of wires(e.g., the wires 169 a, 169 b of FIG. 17) into the interiors of theelongate portions 152 a, 152 b.

The terms “approximately”, “about”, “generally” and “substantially” asused herein represent an amount close to the stated amount that stillperforms a desired function or achieves a desired result. For example,the terms “approximately”, “about”, “generally,” and “substantially” mayrefer to an amount that is within less than 10% of the stated amount.

While the preferred embodiments of the present inventions have beendescribed above, it should be understood that they have been presentedby way of example only, and not of limitation. It will be apparent topersons skilled in the relevant art that various changes in form anddetail can be made therein without departing from the spirit and scopeof the inventions. Thus the present inventions should not be limited bythe above-described exemplary embodiments, but should be defined only inaccordance with the following claims and their equivalents. Furthermore,while certain advantages of the inventions have been described herein,it is to be understood that not necessarily all such advantages may beachieved in accordance with any particular embodiment of the inventions.Thus, for example, those skilled in the art will recognize that theinventions may be embodied or carried out in a manner that achieves oroptimizes one advantage or group of advantages as taught herein withoutnecessarily achieving other advantages as may be taught or suggestedherein.

1. A flow rate assembly comprising: a housing having: a housing axis; afirst end having an inlet positioned along the housing axis; a secondend having an outlet positioned along the housing axis; and ameasurement channel extending along the housing axis and through aportion of the housing between the first and second ends of the housing,the measurement channel having a width perpendicular to the housingaxis; a first outer cup portion positioned at least partly within thehousing, the first outer cup portion comprising: a head portionconnected to a wall of the housing: an elongate portion connected to thehead portion, the elongate portion having a first face facing themeasurement channel; and a plurality of flow channels through the headportion configured to permit fluid to flow past the first outer cupportion through the plurality of flow channels, each of the plurality offlow channels of the first outer cup portion having an end facing an endof another of the plurality of flow channels, so that a boundary wall isformed between facing ends, each boundary wall positioned symmetrical toanother boundary wall relative to the housing axis; and a firsttransducer positioned along the housing axis and within the elongateportion, the transducer sealed from fluid flow past the first outer cupportion, the first transducer having a width perpendicular to thehousing axis and greater than the width of the measurement channel, thefirst transducer configured to generate an ultrasonic signal and todirect the ultrasonic signal through the measurement channel; whereinthe first and second ends of the housing are configured to mate with anopen pipe end in an in-line manner.
 2. The flow rate assembly of claim1, comprising: a second outer cup portion positioned at least partiallywithin the housing, the second outer cup portion comprising: an outerhead portion connected to a wall of the housing: an elongate portionconnected to the outer head portion; and a plurality of flow channelsthrough the outer head portion configured to permit fluid to flow pastthe second outer cup portion through the plurality of flow channels,each of the plurality of flow channels of the second outer cup portionhaving an end facing an end of another of the plurality of flowchannels, so that a boundary wall is formed between facing ends, eachboundary wall positioned symmetrical to another boundary wall relativeto the housing axis; and a second transducer positioned within theelongate portion of the second outer cup portion and sealed from fluidflow past the second outer cup portion, the second transducer having awidth perpendicular to the housing axis and greater than the width ofthe measurement channel; wherein the second transducer is configuredgenerate an ultrasonic signal and to direct the ultrasonic signalthrough the measurement channel toward the first transducer. 3.(canceled)
 4. The flow rate assembly of claim 1, wherein the first outercup portion includes an outlet channel extending between an interior ofthe elongate portion and an exterior of the elongate portion.
 5. Theflow rate assembly of claim 4, wherein the outlet channel extendsthrough at least one boundary wall.
 6. The flow rate assembly of claim1, wherein the housing comprises a first housing portion, a secondhousing portion, and third housing portion positioned between the firstand second housing portions, wherein the measurement channel extendsthrough the third housing portion.
 7. The flow rate assembly of claim 6,wherein one or more electrical components are positioned within a spacebetween the third housing portion and the first housing portion.
 8. Aflow rate assembly comprising: a housing having: a housing axis; a firstend having an inlet positioned along the housing axis; a second endhaving an outlet positioned along the housing axis; a measurementchannel extending along the housing axis and through a portion of thehousing between the first and second ends of the housing, themeasurement channel having a width perpendicular to the housing axis;and a first housing chamber between the measurement channel and theinlet, as measured along the housing axis, the first housing chamberhaving a tapered inner wall; a first outer cup portion positioned atleast partly within the first housing chamber, the first outer cupportion comprising: a head portion connected to a wall of the housing:an elongate portion connected to the head portion, the elongate portionhaving a tapered portion between the first face and the inlet and themeasurement channel; and at least one flow channel through the headportion configured to permit fluid to flow past the first outer cupportion through the at least one flow channel; and a transducerpositioned along the housing axis and within the elongate portion, thetransducer sealed from fluid flow past the first outer cup portion, thetransducer having a width perpendicular to the housing axis and greaterthan the width of the measurement channel, the transducer configured togenerate an ultrasonic signal and to direct the ultrasonic signalthrough the measurement channel; wherein the housing comprises a firsthousing, a second housing, and a third housing, the third housingpositioned between the first housing and the second housing, the flowrate assembly comprising at least one circuit board mounted within ahousing interior formed between the first housing and the third housing.9. The flow rate assembly of claim 8, wherein the head portion of thefirst outer cup portion forms a port for receiving a wire whichcommunicates with the housing interior formed between the first housingand the third housing.
 10. The flow rate assembly of claim 8, comprisingan electrical component mounted within a housing interior formed betweenthe second housing and the third housing.
 11. The flow rate assembly ofclaim 10, comprising a cap positioned at the first end of the housingand forming the inlet, wherein the cap is configured to engage with anopen fluid conduit and the cap is spin welded to the first outer cupportion.
 12. The flow rate assembly of claim 8, wherein the head portionof the first outer cup portion forms a port for receiving a wire whichcommunicates with the housing interior formed between the first housingand the third housing and the transducer is fluidly isolated from fluidflowing through the assembly.
 13. The flow rate assembly of claim 8,comprising an inner cup portion positioned at least partially within theelongate portion of the first outer cup portion, wherein the transduceris positioned within the inner cup portion and wherein a connectionbetween the inner cup portion and the first outer cup portion forms aseal to inhibit or prevent fluid ingress into the elongate portion ofthe first outer cup portion.
 14. The flow rate assembly of claim 13,wherein the inner cup portion has a flat face facing the measurementchannel. 15-19. (canceled)